A hypodermic needle is typically formed from an elongate tube or cannula having a fluid-conducting lumen and characterized by a central axis. The proximal end of the hypodermic needle is typically configured for mating to, or is otherwise affixed to, a fluid delivery device such as a hypodermic syringe. The distal end of the hypodermic needle is typically provided with a pointed tip geometry for piercing elastomeric septums and/or a patient's flesh or tissue so as to deliver the medicament held in the syringe. The practitioner may also employ the hypodermic needle for aspirating fluids held in a vessel such as a vial. This use often entails a practitioner inserting the pointed tip of the needle through a rubber or elastomeric-type seal associated with the vessel so that the practitioner can access the fluid contained within the vessel.
Various considerations merit address when designing the pointed tip of the hypodermic needle. For instance, one would like to minimize the needle penetration force necessary for urging the pointed tip of the needle through the skin and flesh structure of the patient. It is generally recognized that by reducing needle penetration force, the patient will experience less pain, making the injection more comfortable. Another consideration in designing point geometry is to prevent or otherwise minimize "coring". Coring, as the skilled artisan will appreciate, results when a portion of a material through which the needle has penetrated becomes lodged in the lumen adjacent the pointed tip.
Certain efforts in the art have sought to address one or more of the aforementioned concerns. One approach is found in U.S. Pat. No. 3,071,135 (Baldwin et al.). Here, the needle face is characterized by a pair of side facets (or "bevels"), which intersect with a main facet. The heel portion of the needle face includes an external recess which merges with a smoothly rounded surface or edge portion of the lumen opening. It is stated in this patent that the provision of the needle recess relieves tension of a membrane flap created upon entry of the needle, thereby reducing the penetration force. U.S. Pat. No. 2,560,162 (Ferguson) provides a similar structure, albeit with the provision of an additional pair of forward side bevels. An emphasis of this patent is that the provision of the recess (here referred to as a depression) prevents or minimizes the severing of a plug from a layer or layers being pierced by the needle. U.S. Pat. No. 3,308,822 (DeLuca) has as its objective minimizing the penetration force of a needle so as to minimize pain incident to an injection. This patent states to create, from an initial piercing point of the flesh, three substantially straight lines in the form of the letter "Y". It is stated that by forming the "Y" shaped cut, three substantially V-shaped flaps are formed, the three angular edges of which are capable of extension into a circular form in the opening of the skin, thereby preventing extensive stretching or tensioning of the edges of the cut. The needle point employs five faces produced by a series of five grinds, with the last two grinds resulting in bevels disposed not adjacent the opening of the needle, but rather on the back of the needle away from the opening. U.S. Pat. No. 2,409,979 (Huber) relates to a hypodermic needle also intended to reduce pain as the needle penetrates the tissue. Huber appears to describe a primary bevel mating with a pair of beveled surfaces that meet at a curved surface of diminishing area adjacent the end portion of the needle.
Despite the attempts in the art to arrive at a needle point geometry to lessen needle penetration forces, there continues to exist a need for a needle point geometry which displays reduced needle penetration forces and, hence, reduces the pain or discomfort level experienced by a patient. Such a needle point geometry is disclosed herein.